1. Field of the Invention
The present invention relates to a heating resistance element component (thermal head) which is used in a thermal activation device, and selectively drives a plurality of heating elements based on thermal activation data to thermally activate a thermosensitive adhesive layer provided on a rear side of a sheet-like base.
2. Description of the Related Art
There is generally known a thermal activation device which performs recording and thermal activation to a thermal activation starchy sheet including a thermosensitive adhesive layer formed on a rear surface side of a recording surface of a sheet-like base. The thermosensitive adhesive layer is formed of, for example, a material which is not adhesive at about room temperature but expresses adhesion through thermal activation by being heated to about 50 to 150° C. In the thermal activation, a large area needs to be heated to obtain adhesion, which requires a considerable amount of thermal energy. Therefore, in order to avoid a problem such as an increase in temperature of an entire device and decreased operating time when powered by battery, for example, it is desirable that a thermal head consuming little electric power, which is disclosed in JP 2007-83532 A, be used in the aforementioned thermal activation device.
The thermal head disclosed in JP 2007-83532 A is formed with a hollow portion in a region opposed to a heating portion of a heating resistor. Ideally, the hollow portion should be provided over a region much larger than a region where the heating resistor is formed. However, when the hollow portion is provided in the region much larger than the region where the heating resistor is formed, a mechanical strength of a substrate decreases.
In addition, when the mechanical strength of the substrate is intended to be sufficiently ensured, the hollow portion cannot be formed in the region much larger than the region where the heating resistor is formed. As a result, heat generated in the heating element diffuses over the entire substrate, which results in a decrease in heating efficiency.